The present invention relates to a wobbling irrigation sprinkler head and especially to a wobbling sprinkler head for mounting to a central pivot irrigation system or the like.
It has become common practice to use center pivot irrigation systems in the irrigation of large fields and these typically comprise a long water conduit which is pivotally connected at one end to a source of water under pressure. The conduit arm is carried in an elevated position by a plurality of spaced wheels or wheel towers which are powered by hydraulic, pneumatic, or electric motors to rotatably sweep the central conduit over a circular pattern in a field. The central conduit includes a plurality of water sprinkling heads spaced over its length for distributing a spray of water on the circular field area as the center pivot irrigation conduit passes thereby. Center pivot irrigation systems have been successful for uniform distribution of water over a field crop and initially were operated at reasonably high water pressures. Current systems typically work with a somewhat lower water pressure and require that sprinkler heads distribute water evenly as the center pivot irrigation conduit moves through a field. A typical patent for a center pivot irrigation system can be seen in the Vikre patent, U.S. Pat. No. 4,356,972, which mounts the sprinkler heads on top of the central irrigation center pivot conduit. The sprinkler head uses a deflector head for deflecting the water with a grooved deflector pad. Other self-propelled mechanically moving irrigation machines can irrigate in a different manner, such as moving laterally in a straight line through a field.
There have been a number of wobbling sprinkler heads used in the past in which the water distribution head of the sprinkler, instead of being rotated in a smooth rotation or instead of following one of the other sprinkler patterns, has a water distribution head which wobbles in a rotating fashion to provide a more even distribution of water. In addition, the wobbling sprinkler head is sometimes rotated to provide a rotating sprinkler having a wobbling head the end thereof. In the Clearman patent, U.S. Pat. No. 4,487,368, and in the Clearman patent, U.S. Pat. No. 4,773,594, a control pattern wobbling sprinkler is provided in which a rotating sprinkler head has a wobbling water distribution head mounted on the end thereof which has a plurality of vanes formed in the wobbling portion of the head to force a wobbling motion which results from the loose connection between the distribution head and the supporting arm of the sprinkler head. In the sprinkler of these two patents, a base is provided for ground support and a rotating sprinkler head has the end of the rotating arm bent at an angle so that the loosely attached wobbling head tilts groundward when not being used. Upon initiation of water under pressure to the head, the head is already in a cocked position and forces a rotating action which causes a wobbling rotation of the water head portion. In the J. M. Hait patent, U.S. Pat. No. 3,009,648, an irrigation system is provided in which the sprinkler head has a rotating stream of water issuing therefrom but allows a deflection head to move back and forth. In the J. O. Hruby, Jr. patent, U.S. Pat. No. 3,034,728, a lawn sprinkler is shown which has a centrally disposed and vertically extending stem which is made to rotate by the action of the water passing through the sprinkler. The stem is loosely mounted and has an uneven deflecting portion to produce a rotating action of the spray. In the M. S. Aubert patent, U.S. Pat. No. 3,091,400, a dishwashing machine has a rotary wobbling spring head which is driven by the water momentum to wobble the head in a dishwasher.
In the present invention, a wobbling sprinkler head is used on a central pivot irrigation system or the like in which the sprinkler head is attached to a water pipe from the top of the central pivot water supply and forms a "U" in the pipe to hold the sprinkler head in an upright position. A wobbling sprinkler head of the present type requires that the head be cocked in some manner in order to initiate the wobbling of the loosely held head portion and utilizes a magnet working in connection with a ferric metal washer mounted in the sprinkler head base and in the deflection head to force a tilt in the deflection head portion when water pressure is not driving the wobbling sprinkler head. In addition, specially designed water deflecting grooves in the deflection pad helps initiate the wobbling and rotation of the deflection head to provide a more even distribution of water by the wobbling action as the sprinkler head distributes water during the movement of the central water supply conduit moving through a field on wheeled supports.